Illusions

An illusion is a distortion of the senses, which can reveal how the human brain normally organizes and interprets sensory stimulation.

Solso, R. L. in Cognitive psychology (6th ed.)

Illusions may occur with any of the human senses, but visual illusions ( optical illusions ) are the best-known and understood. Below are some optical illusions I tried to recreate using SketchUp and three.js. Check out and see how you see them.

Ames Window

Also called Ames trapezoid, this window appears to be oscillating while it's actually rotating. Learn more about it @Veritasium

Note: Use mouse or touch to interct with the window

Spinning Ballerina

This is a silhoutte illusion. There are no depth cues for us to tell which is her left side and which is right. So when the dancer spins she appears to be spinning both left and right. Learn more about it @nytimes

Circle Illusion

Here we see a series of dots rotating within a larger circle. But what we miss is all the dots are moving in a straight line, the diagnol passing through them. Click on the circle to see it.

Dual Axis Illusion

This is similar to the Spinning Ballerina but the shape here seems to rotate about both the vertical and horizontal axes. Hence the name Dual Axis. Stare at the intersection point for the axis of rotation to change